Power transmission



y 1945. H. w. Gl LFlLLAN 2,375,782

. POWER TRANSMISSION Filed Aug. 8, 1941 INVENTOR MTTORNE S;

Patented May 15, 1945 UNITED STATES;

PATENT OFFICE POWER TRANSMISSION Henry W. Gilfillan, Detroit, Mich,asslgnor to Chrysler Corporation, Highland Park. Mlcln, a corporation ofDelaware Application August 8, 1941, Serial No. 408,030 4 Claims. (01.123-179) This invention relates to motor vehicles and refers moreparticularly to improvements in power transmission therefor.

In certain types of power transmission systems employing an overrunningdrive and electrical control device it is sometimes impossible to starta dead engine by towing (pushing or pulling) the car where the usualstorage battery has dropped in voltage to a point where it will not.coil for the electrical control device and a resistance so arrangedthat for normal operation of thetransmission, the resistance, is inseries with the coil but for cold starting, where the battery voltage isdown, the resistance is shunted out. Such arrangement furthermoreaccommodates the use of a larger coil than normal because of theresistance in series with thecoil under normal conditions of maximumbattery voltage.

Further objects and advantages of my invention reside in the novelcombination and arrangement of parts more particularly hereinafterdescribed and claimed; reference being had to the accompanying drawingin which:

Fig. 1 is a longitudinal sectional elevational view through a typicaltransmission showing my invention incorporated therewith.

Fig. 2 is a detail sectional elevational view taken in accordance withline 2--2 of Fig. 1.

Fig. 3 is a wiring diagram.

Referring to the drawing, I have illustrated I my invention inconnection with a transmission wherein one or more pairs of relativelyengageable drive control elements are arranged to control a transmissiondrive, the drivb control elements being in the form of a clutch andpreferably of the frictionally engageable magnetically controlled typeas will presently be more apparent.

Referring to the transmission A of Fig. 1, reference character Itrepresents the driving shaft adapted to receive power from the usualvehicle engine, this shaft carrying the main drive pinion H which is inconstant mesh with gear l2. This gear drives countershaft l3 through anoverrunning clutchB of the usual type such that when shaft l drives inits usual clockwise direction 5 (looking from front to rear) then clutchB will engage to lock gear l2 to countershaft l3 whenever gear |2 tendsto drive faster than the countershaft. However, whenever this gear l2tends to rotate slower than the countershaft then I" clutch B willautomatically release whereby shaft l0, under certain conditions, mayreadily drop its speed while countershaft l3 continues to revolve.

Countershaft I Scomprises cluster gears l4, l5

l5 and I6 which respectively provide drives in first,

third andreverse. Freely rotatable on the driven or output shaft H,which is axially aligned with shaft ID, are the first and third drivengears |8 and I9 respectively in constant mesh with countershaft gears l4and 15. A hub 20 is splined on shaft l1 and carries therewith ashiftable sleeve 2| adapted for shift in any desired manner, such asmanually, from the Fig. 1 neutral position either rearwardly to clutchwith teeth 22 of gear ID or else forwardly to clutch with teeth 23 ofgear l9. If desired, toothed blocker synchronizer rings 24 may belocated between sleeve 2| and teeth 22, 23 to insure shift of sleeve 2|only when ,the parts to be clutched are synchronized as is now wellknown and as set forth, for example,

in the copending application of O. E. Fishburn, Serial No. 180,840 filedDecember 20, 1937, now Patent No. 2,333,165.

Shaft 11 also carries reverse driven gear 25 fixed thereto. A reverseidler gear 26 is suitably mounted so that when reverse is desired, idler25 is shifted rearwardly into mesh with gears l6 and 25.

First, third and reverse speed ratio drives and 4 neutral are preferablyunder manual shift con- Hold the vehicle driver by manipulation of.

sleeve 2| or gear 26.

First is obtained by shifting sleeve 2| to clutch with teeth 22, thedrive passing from pinion Ill to gear |2 thence through clutch B tocountershaft l3. From the countershaft this drive is through gears l4,l8 and sleeve 2|, hub 20 to shaft ll.

Third is obtained by shifting sleeve 2| forwardly to clutch with teeth23,- the drive passing frompinion II to countershaft l3 as before,thence through gears I5, I9 and sleeve 2| to shaft l1.

Reverse is obtained by shifting idler 26 into mesh with gears l6 and 25,sleeve 2| being in neutral, the reverse drive passing from shaft It tothe countershaft 13 as before, thence through gears I8, 26 and 25 toshaft H.

I have provided clutching means comprising an electromagnetic device Cfor operably connecting and disconnecting pinion fit and gear is so asto step-up the speed ratio drive irom first to second and from third tofourth which is a direct drive speed ratio. When driving in first,second is obtained by engaging clutch C, the drive then passing frompinion i I through clutch C to scam l9 and it thence throughcountershaft E3 and gears id, to to sleeve 2! and shaft l1, clutch Boverrunning. By similar operation, the drive may he stepped up fromthird to direct by engaging clutch C accompanied by overrun at clutch B,the drive passing from pinion it through clutch C to gear it thence tosleeve 29 and shaft ll. When driving in second or fourth, first or thirdmay be respectively obtained simply by releasing clutch C accompanied byspeeding up the engine to engage clutch B.

Clutch C comprises a flux-conducting coil-=receiving annular channeledelectromagnet 2? which, in the illustrated type of transmission iscarried by gear l9 and always rotating therewith,

the electromagnetjbeing disposed between gears' M and i8.

Welded or otherwise fixed to the outer annulus of electromagnet 27 is aforwardly proiectingannular sleeve 28, of low permeability material,this sleeve having internal splines 29, for receiving the tongues 33 oithe tin flux-con ducting friction driven disks or elements 3|. Betweenadjacent disks ti there is a generally similar driving disk element 32,these disks ter minating outwardly short of sleeve 28 and hav i ng innertongues 33 for engagement with splines 34 of the rear extension 35 ofpinion ll.

, A magnetic pressure plate 36 is seated on extension 35 formovement'toward electromagnet From conductor 43 the circuit extendsthrough.

a brush 48 running on conductor slip ring 41 which is carried by sleeve23 and thence through coil 38 to a, ground 48 at the transmission.

For normalcontrol of clutch C the switch 45 will remain open and switchll willbe opened,

ciently low, say around 3 volts for example, then 21, the disks 3!, 32being disposed in closely associated relationship between plate 36 andelectromagnet 21 so that when the electromagnet is energized, as willpresently be apparent, the flux operates in a closed path or magneticcircuit around electromagnet 27, through disks 3!, 32 and plate 36 suchthat the plate 36 and disks SI, 32 are drawn toward. the electromagnetserving to frictionally pack the disks together and thereby drivinglyconnect pinion M with gear IS. A small portion of the flux in theaforesaid magnetic circuit is shunted at each disk 3!, 32

but this is utilized to draw the disks-together.

To insure most of the flux following the complete circuit, each disk 3|,32 is formed with a plurality of axial slots 31 therethrough, theseslots being registered with each other so that most of the flux isprevented from shunting through the disks and is made to travel throughthe prescribed circuit including plate 3B. In order to disengage clutchC it is only necessary to de-energize the electromagnet 21.

In order to energize the electromagnet 21 I- have provided a coil 33disposed within the channel of the electromagnet for rotation therewith.

Referring to Fig. 3 I have illustrated my control system comprising a.source of energization as at storage battery 33 having a ground 40. Fromthe resulting amperage at coil 36 of around 1% amperes would ordinarilybe insuflicient to engage clutch C and hence the engine could not bestarted by towing the car. At such times the driver need only to closeswitch to so as to shunt the resistance id and, with switch closed, coil38 would receive a normal 3 amperes instead of 1% amperes. The foregoingfigures are, of course, cited merely as illustrative and may varyaccording to the selection of battery, coil, resistance, and otherparts. If the external re-' sistance so is equal to the internalresistance of the coil 33, the clutch C may be fully engaged withone-half the normal desired battery voltage. r

After the engine has been started and the system restored for normaloperation, as by building up the voltage in battery 33 or by supply ofadequate voltage by the usual generator, switch 45 may be opened and thesystem restored to normal control by switch fl-l with resistance at oncemore in series with coil 33.

Switch 45 may, of course, be closed, toadvantage at other times thanwhen it is desired to drive shaft H) from shaft H, as when the voltagefor any reason is inadequate to fully engage clutch C with theresistance operating in series with the coil.

The various electrical parts will, of course, be suitably electricallyinsulated so as to function as intended.

I claim:

1. A transmission for driving a motor vehicle comprising in combinationa driving shaft adapted to receive drive from the engine, a driven shaftadapted to receive drive from the driving shaft for driving the vehicle,an electrically energizable clutch device adapted when energized toconnect said shafts for drive transmis-' sion therebetween, a field coilfor energizing said device, a storage battery, a resistance normally inseries with said field coil during all energization of said device fordriving said vehicle, circuit means including said coil, saidresistance, and said battery, and driver controlled switch means forshunting said resistance out of said circuit means at the will of thedriver upon abnormal drop in voltage of said battery to thereby providethe normally required energizing current in said coil to energize saiddevice and connect said shafts for drive transmission therebetween andenable said vehicle engine to be started by towing said vehicle.

2. In a drive for a motor vehicle having an engine, a driving shaftadapted to be driven from the engine, a driven shaft adapted to bedriven from said driving shaft for driving the vehicle,

a. clutch for controlling drive transmission'between said shafts suchthat when said clutch is operative said shafts are drivingly connectedand when said clutch is inoperative said shafts are drivinglydisconnected, an electrically energizable field coil adapted to beenergized for effectmg said operation of said clutch, a source ofelectrical energy for said field coil comprising a storage battery, aresistance normally in series with said field coil for all operation ofsaid clutch for driving said vehicle, electrical circuit means for saidcoil, battery, and resistance, and switch means positionable to shuntsaid resistance out of said circuit means, said battery having a voltagenormally sufficient to provide required current for energization of saidcoil to efiect operation of said clutch but being incapable,

of providing required current for effecting said operation of saidclutch with said resistance in series with said coil as aforesaid uponan abnormal drop in voltage of said battery, said switch means beingadapted to be so positioned as to normally maintain said seriesarrangement of said resistance and coil during all drive of the vehiclewhen the voltage of said battery is sufficient to effect said operationof said clutch, and said switch means being positionable at the will ofthe driver as to effect said shunting of said resistance when thevoltage of said battery has dropped as aforesaid thereby to provideenergizing current to said coil in amount sufficient to eifect saidoperation of said clutch and enable drive of the engine for starting thesame by towing the vehicle.

3. In a motor vehicle of the type equipped with a storage battery forsupplying required energizing current to the coil of an electricallyenergizcircuit between the battery and coil to thereby provide said coilwith sufiicient energizing currentto enable positive engagement of saidclutch and towing the vehicle with the clutch so engaged to turn theengine over. 4. A transmission for driving a motor vehicle comprisingadapted to receive drive from the engine, a driven shaft adapted toreceive drive from the driving shaft for driving the vehicle, anelectrically energizable device adapted when energized to connect saidshafts for driving transmission therebetween, a field coil forenergizing said de- Vice, 9, storage battery, a resistance normally inseries with said field coil during all energization of said device fordriving said vehicle, circuit means including said coil, saidresistance, and said battery, and switch means operable to shunt saidresistance out of said circuit means such that when the battery voltagedrops abnormally then operation of said switch means will provide thenormally required energizing current in said shafts for drivetransmission therebetween, and

enable said vehicle engine to be started by towin combination a drivingshaft coil to energize said device and connect said

